R Downloading multiple file from FTP using Rcurl

问题

I'm a new R. user. I am trying to download 7.000 files(.nc format) from ftp server ( which I got from user and password). On the website, each file is a link to download. I would like to download all the files (.nc).

I thank anyone who can help me how to run those jobs in R. Just an example what I have tried to do using Rcurl and a loop and informs me: cannot download all files.

library(RCurl)

url<- "ftp://ftp.my.link.fr/1234/"
userpwd <- userpwd="user:password"
destination <- "/Users/ME/Documents"
filenames <- getURL(url, userpwd="user:password", 
ftp.use.epsv = FALSE, dirlistonly = TRUE)

for(i in seq_along(url)){
  download.file(url[i], destination[i], mode="wb")
}

how can I do that?

回答1:

The first thing you'd see is that the files in your directory, ie the object filenames, would be listed as one long string. To obtain an object of all file names as a character vector, you may try:

    files <- unlist(strsplit(filenames, '\n'))

From here on, it's simply a matter of looping through all the files in the directory. I recommend you use the curl package, not Rcurl, to download the files, as it's easier to supply auth info for every download request.

    library(curl)
    h <- new_handle()
    handle_setopt(h, userpwd = "user:pwd")

and then

    lapply(files, function(filename){
    curl_download(paste(url, filename, sep = ""), destfile = filename, handle = h)
    })

来源：https://stackoverflow.com/questions/39705379/r-downloading-multiple-file-from-ftp-using-rcurl